POSTURAL ANALYSIS OF AIR FILLING OPERATORS WORKING AT PETROL FILLING STATIONS

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1 Vol. X & Issue No. 5 May POSTURAL ANALYSIS OF AIR FILLING OPERATORS WORKING AT PETROL FILLING STATIONS Iqbal Ahmed Khan B.P. Agrawal Abstract The present study is focused on posture analysis of the workers working as air filling operators at various petrol filling stations in Delhi NCR. They are continuously working since morning to late night regularly and for whole life. During this period it is observed that they have to occupy a definite posture to perform a specific activity. Their sets of activities are definite and do infinite number of times daily. It depends upon number and type of vehicles i.e. two wheelers/three wheelers/four wheelers etc. arrived for filling air in the tires, at petrol filling stations. The personnel who are working as air filling operators are large in numbers (at least one operator is required for each petrol filling station) if they considered at country level. Apart from these, lot of tyre punctures shops in the cities where similar kind of task is carried out. Also they belong to different age groups and doing repetitive task in nature. The repetition of task can aggravates work related musculoskeletal disorders (WMSDs) such as upper limb extremities, the lower back area, lower limbs, muscles, joints, tendons, ligaments, nerves, bones and the localized blood circulation system etc. in the operators. Keeping this in mind the working postures at the time of air filling of the air filling operator were recorded by Video and still photography, and these images were used for postural analysis. The postural analysis tools Rapid Upper Limb Assessment (RULA), Rapid Entire Body Assessment (REBA) and Quick Exposure Check (QEC) are used to determine the risk assessment involved in the working of air filling operators. The result of RULA and REBA scores 4 and 5 are respectively obtained. The RULA showed, low risk in performing the task and change may be needed in working postures of air filling operators'. Also the REBA revealed that medium risk is in performing the task and further investigation and change is required soon. Further QEC results showed that back score, shoulder/arm score, wrist/hand score are moderate. But neck score and work pace score are very high and high respectively. On the basis of findings of the present work and subsequent discussions in the light of previous researches are carried out and conclusions are drawn. Key words: RULA, REBA, QEC, postural analysis, WMSD INTRODUCTION When an individual go at petrol filling station for filling fuel in his/her vehicle it is a common tendency of everyone to check air pressure in the tires. Air filling operator set the pressure on the digital panel of air compressor, takes an air pressure pipe on his hand(s), and moves towards the tyre of the vehicle, bent in a particular position, presses the valve of tube/tyre and fills the air. When the air pressure is reached at desired pressure level a beep is listen by the operator and after that operator remove the air pipe from valve and stand-up and move towards the next tyre to fill the air in the tyre/tube and this process is continues till the work is complete. The same process is repeated for all the vehicles in a day and infinite number of times and for whole life of the operator. For repetition of work an air filling operator takes definite postures to perform the task. This repetition of work of the workers in any field aggravates the work related musculoskeletal disorders (WMSDs). It is also known as RSI (repeated strain injury), CTD (cumulative trauma disorder), over use syndrome etc. Due to repeated straining body tissue and not allowing enough time to heal are believed to cause progressive discomfort, pain, and ultimately disability to continue regular work. The factors which are believed to be associated with WMSD are repetition/duration/rest short cycle time (<30 sec), static work, joint deviations awkward postures, velocity and acceleration- speed of movement, internal forces on joints, vibration, coldness and non occupational factors are fitness level, mental stress, smoker, hobby etc. LITERATURE REVIEW In the past many researches were conducted in the this field for improvement in working postures of the operators' who are working in different industries to minimize the work related musculoskeletal disorders (WMSDs). A study [1] revealed that awkward working postures, static load and task invariability are the factors which increase musculoskeletal symptoms. Also work-related musculoskeletal disorders (WMSDs) are adversely affects on labour turnover, absenteeism, poor quality and reduced productivity in the industries [2]. The work related a musculoskeletal disorder (WMSD) is an injury or disorder of the muscles, nerves, tendons, joints, cartilage, and spinal discs. It is not an acute injury, rather a chronic disease which develops over a passage of time. And also MSD is related to manual tasks and is a source of significant pain, disability and substantial burden on modern societies. Statistics showed that more than 30% of all occupational injuries are musculoskeletal injuries associated with manual tasks [3].WMSD have also heavy economic costs to the companies and to health care systems. The costs are due to loss of productivity, training of new workers and compensation costs [4]. The ageing of the work force are also a contribution tothe wide spread of WMSD, since the propensity for developing a WMSD is related more to the difference between the demands of work and the worker's physical work capacity that decreases with age [5]. Understanding ergonomics risk factors are essential because there is indication that ergonomic risk factors are usually related to musculoskeletal disorders of the upper extremities and the low back [6]. PROBLEM STATEMENT In the light of the above mentioned facts and literature review it is revealed that in the past either few or no study was conducted on the air filling operators who are working at petrol filling stations. The present study is focused on air filling operators working postures at petrol filling stations to overcome the WRMSDs. Ergonomics postural analysis tools such as Rapid Upper Limb Assessment (RULA), Rapid Entire Body 06

2 Assessment (REBA), and Quick Exposure Check (QEC) are used to evaluate the risk factor associated with air filling operators working postures. c. Start' the work on hearing the sound of the buzzer and 'Stop' the task after listening the sound of buzzer Now experimenter performed the following steps for filming the task of the air filling operator; a. Paste the black colour tape on the neck, hands, trunk and legs of the operator so that any change in angle of body parts are to be determined precisely b. Press the buzzer to 'Start' the work. Do filming by Sony Cyber shot digital camera of the complete task of air filling operator. Again press the buzzer to 'Stop' the task RULA: The Rapid Upper Limb Assessment (RULA) was developed by McAtamney and Corlett [7] to measure the musculoskeletal risk caused by mainly sedentary tasks where upper body demands were high and work related upper limb disorders are reported. RULA (Table 1) assesses the posture of the worker. METHODOLOGY For postural analysis of the air filling operator, following steps has been taken; I. For video graphy following items are used; a. Sony Cybershot DSC-W830/S, 20.1 MP Digital Camera, Black colour cello tape and Buzzer ii. Explained the purpose of present study to the air filling operator and give him instructions so that he would be perform task in normal pace and take postures which are essential to complete the task. iii. Instructions to the operator; a. Don't do unnecessary motions of your body part such as moving finger (s), thumb(s), legs foot etc. b. Movement of the body should be uniform and Perform the task in normal pace Table 1: RULA Employee Assessment Worksheet 07 DOI:

3 Table2: Classification of Risks according to the Scores of RULA REBA: REBA (Rapid Entire Body Assessment) postural analysis tool was developed by Hignett, S.and Mc Atamney, L. [8] to provide a quick and easy postural analysis of the worker for whole body activities (static and dynamic giving musculoskeletal risk action level. REBA (Table 3) assesses the posture of the worker. Steps 1-6 are to be carried out for Neck, Trunk and Leg analysis (A) and use the Table A of Table 3 to find out the score. Further, steps 7-13 are to be followed for Arm and Wrist analysis (B) and use Tables B and C of Table 3, respectively to find out the scores. Also the detailed procedure of posture analysis of employee is given in Table 3. Now, final score of REBA analysis is further use in Table 4 to obtain the level of musculoskeletal disorders (MSD) risk and action to be taken is recommended. Table 3: REBA Employee Assessment Worksheet 08 DOI:

4 Quick Exposure Check (QEC): It is developed by Li and Buckle [9], in which both the assessor and worker which is to be assessed are involved. The holistic assessment of all the elements of a work system allows for the implementation of the optimal solution to ergonomic risk reduction. On the net at website http//: freiz com the QEC observer's assessment sheet calculator is available. Answer all the given questions. It shows results in the form of various scores for back, shoulder/arm, wrist/hand, neck etc. as shown in table 5. Through viewing scores find out the corresponding value of MSD risk assessment from Table 5. RESULTS 1. RULA analysis: Employee Assessment Worksheet (RULA-EAWS) is used which is shown in Table 1. After following Steps 1-15 of RULA-EAWS, a final score is obtained. Further final score of RULA, see in Table 2 to determine the risk which is associated in working and necessary actions is to be initiated accordingly. 09 DOI:

5 A. Arm and Wrist Analysis: From figure 2, upper arm, lower arm and wrist positions of the operator are measured in angles. And the corresponding scores are obtained from Table 1. These are as follows; Step 1: Locate Upper Arm Position Upper arm Angle (26 ), Upper arm Score = 2 Step 2: Locate Lower Arm Position Lower arm Angle (82 ) From Table 1, Lower arm Score = 1 Step 3: Locate Wrist Position Wrist Angle (30 ) From Table 1, Wrist Score = 4 Ulnar Deviation Score = 1, Total score 3 + 1= 4 Step 4: Wrist Twist: From Table 1, Wrist Twist Score = 1 Step.5: Look up posture Score in Table A of Table 1: Using values, which are obtained from Step1 to 4, Locate in Table A and find out the score. Score = 4 Further precedes the steps 6-8 of RULA analysis according to Table 1. Step 6: Add muscle Score: It is < 10 minutes, so Score = 0 Step 7: Add Force/Load Score: Load is < 4.4lbs, so Score = 0 Add values from step 5 to step 7, = 4 Step 8: Find Row in Table C of Table 1 B. Neck, Trunk and leg Analysis: For neck, trunk and leg analysis first see the air filling operator's initial position (Figure 3) before doing work. Now during working his neck is tilted towards the chest as shown in figure 4. Also his trunk posture was observed in figure 5, while working. The experimenter measured the angles of operator's legs (Figure 6). The angles of neck, trunk and legs are measured and steps 9-11 of neck, trunk and leg analysis are performed according to Table 1 of RULA-EAWS, and scores are calculated. These steps are; Step 9: Locate Neck Position Neck Angle (32 ) From Table 1, Neck Score = 3 Step 10:Locate Trunk Position Trunk Angle (33 ) From Table 1, Trunk Score = 3 0 Step 11:Legs Position: Leg Angle (22 ) From Table 1, Leg Score = 1 Now locate these scores of neck, trunk and leg in Table B of Table 1. Step 12:Look-up posture in Table B of Table 1. Score = 4 Follow the process of Steps 13-14, according to Table 1of RULA EAWS. Step 13:Add muscle Score: It is < 10 minutes, Score = 0 Step 14:Add Force/Load Score: Load is < 4.4lbs, so Score = 0 Step 15:Find Column in Table C of Table 1 Add values from steps to obtain Neck, Trunk and Leg score = 4 Now locate the step 8 score (4) in row and step 15 score (4) in column of Table C of Table 1 respectively. And see the corresponding score, which comes here 4. This is the RULA score. Further RULA score (4) is used to see the information in Table 2. The information obtained from Table 2 is, 3-4 low risk, change may be needed. 1. REBA analysis: For this analysis REBA Employee Assessment Worksheet (REBA-EAWS) is used which is shown in Table 3. After following Steps 1-15 of REBA, a final score is to be obtained. Further this obtained final score of REBA, see in which row exits in Table 4 to determine the risk which is associated in working and necessary actions is to be initiated accordingly. A. Neck, Trunk and leg Analysis: For neck, trunk and leg analysis first see the air filling operator's initial position (Figure3) before doing work. Now during working his neck is tilted towards the chest as shown in figure 4. Also his trunk posture was observed in figure 5, while working. The experimenter measured the angles of operator's legs (Figure 6). The angles of neck, trunk and legs are measured and steps 1-3 of neck, trunk and leg analysis is performed according to Table 3 of REBA-EAWS and scores are calculated. Step 1: Locate Neck position: Angle (32 ) From Table 3, Neck Score = 2 Step 2: Locate Trunk position: Angle (33 ) From Table 3, Trunk Score = 3 Step 3: Legs position Angle (> 60 ), From Table 3, Leg Score = 2 Step 4: Look-up posture Score in Table A of Table 3. Using values from steps 1-3, Table A of Table 3, find the score; Score = 5. Follow the process of Steps 5-6 according to Table 6 of REBA -EAWS Step5: Load score: Load, 11 bs, score = 0 Step 6: Find row in Table C of Table 3. Score = = 5 B. Arm and Wrist Analysis: Initially air filling operator was stand in vertical position (Fig.1) and then moved to the working posture i.e. to fill the air in the tyre as shown in Figure 2. Further, experimenter measured upper arm, lower arm and wrist angles which are shown in figure 2. After measuring these angles from the figure 2, arm and wrist analysis (A) is carried out according to Table 3. Step 7: Locate Upper Arm Position Upper arm Angle (26 ) From Table 3, Upper Arm Score = 2 Step 8: Locate Lower Arm Position Lower arm Angle (8 ) From Table 3, Lower Arm Score = 1 Step 9: Locate Wrist Position: Wrist Angle (30 ) From Table 3, Wrist Score = 2 Step 10:Look up posture score in Table B of Table 3. Score = 2 Step 11:Add coupling Score: Score = 1 Step 12:Find Column in Table C of Table 3. Add values From Step 10 to 11: Score = 2 + 1= 3 Step 13:Activity Score, Score = 1 REBA Score = Score in Table C of Table 1 + Activity Score REBA Score = 4 + 1= 5 REBA Score = 5. The REBA Score is 5. This REBA score 5 is seen in Table 4. The information obtained from Table 4 is, 4-7 Medium Risk, Further Investigation, and Change Soon. Apply QEC: At website http//: freiz com, QEC observer's assessment sheet calculator is available. Answer all the given questions. The results obtained in the form of various scores are as follows; Back score: 26 / Shoulder/Arm score: 26 / Wrist/Hand score: 26 /Neck score: 16 / Driving score: 1 /Vibration score: 1/ Work Pace score: 9 /Stress score: 9 Through viewing these scores in table 5, find the corresponding value of risk assessment from table 5. The results showed that 10

6 back score, shoulder/arm score, wrist/hand score are moderate. But neck score and work pace score are very high and high respectively. DISCUSSIONS AND CONCLUSIONS The major and important finding is RULA score 4, it designates, 3-4 low risk, change may be needed. From the observations it is also evident that air filling operators' neck, upper am, lower arm and trunk are innumerous times bents and take definite angles for performing the task. A specific awkward posture of the operator repeat infinite number of times produces work related musculoskeletal disorders in his upper limb. RULA analysis also suggested that risk is associated in the performing task so it has to be changed. This result is in line with the past researches such as D. N. Agrawal et.al. [10] considered a tractor trolley manufacturing unit in which welding had been done on kneeling posture as the fixture used for welding was placed on the ground. Continuously worker has to sit on that posture and has to perform welding work. It was observed that due to continuous kneeling posture worker got fatigued frequently and musculoskeletal problems were identified in them which were then validated by using RULA. A research was conducted by Alireza Choobineh et.al. [11] on musculoskeletal problems among workers of an Iranian communication company. They found that there was very high score of RULA (action level 3 & 4). RULA score could be reduced by designing ergonomic workstation and it might reduce the WRMDs among the workers. RULA showed that the awkward working postures and static work had been found to be the major risk factors that the workers encountered. Improper design and ill arrangement of workstation were the causes of postural problems and could have been cured by redesigning workstations based on ergonomics principles and would have reduced the RULA Grand Score. Chowdury M. L. Rahman [12] was conducted a study on work postures of workers working in a ceramic industry through rapid upper limb assessment (RULA)and it has been found that most of the workers have been exposed to the upper limb discomfort which has contributed to the bad work postures. Through the analysis of RULA, it has been revealed that no posture is risk free for the workers working in the production section of the ceramic industry. According to RULA, further investigation is needed for 15.38% of workers, prompt investigation and changes are required for 41.02% of the workers and finally 43.59% of the workers need immediate investigation and changes in order to maintain the desired performance level and increase the productivity as well. Another important finding is REBA score 5 which shows, 4-7 medium risk, further investigation, and change soon. It is clear from the photograph of the air filling operator that his working posture is awkward and could be harmful to him, if it continues for long duration. Many studies were conducted in the past and found similar results such as a study conducted by Karthikeyan Mathesan et. al.[13] on vertical drilling operation in a laboratory work place using engineering students. The engineering students were divided into 16 experimental batches and each batch was accessed by one safety professor, two lab engineers and four lab technical supervisors. Every movement of subjects was closely observed and evaluated by two ergonomic tools Rapid Entire Body Assessment (REBA) and Rapid Upper Limp Assessment (RULA), using Ergo Fellow 2.0 software. The overall result shows that the manual feeding (operation no 3) has the highest risk value with a REBA and RULA percentage of and 85.71, respectively, whereas the operation of removing the workplace from the worktable have a REBA percentage of 26.6 and RULA percentage of 42.85, which indicates the lower level of risk. Ergonomic aspects have to be included in designing of operating procedure for drilling operation, which helps in reducing the existing level of risk. Abdul majid Garkaz et. al. [14] study was focused on ergonomic assessment of sina car montage industry employees' working positions in Hamedan. 120 workers with 60 occupational duties from different sections were selected as samples and REBA Technique was carried out to assess musculoskeletal loads on workers due to their postures, repetition, and force. During last year, most suffering from MSDs in studied persons was related to waistline region (34.4%) that was followed by neck and wrist (each of them 31.2%). No tasks were placed in action level of 0 and few cases were in action level of one. Thereby, further actions, ergonomic designing solutions, and multiple preventions are necessary. QEC results showed that back score, shoulder/arm score, wrist/hand score are moderate. But neck score and work pace score are very high and high respectively. It is because of air filling operator bent his neck again and again to see the position of the tube/tyre valve and fix the air pipe valve into it to fill the air very frequently. Obviously when operator repeats this posture in innumerous times faces the neck pain which is the outcome of the working posture of the operator. The similar kind of results are obtained by previous researches such as Emre Ozgur Bulduk et. al. [15]examined the risk factors that are involved in the development of WMSDs in taxi drivers. In total 382 taxi drivers were observed using Quick Exposure Check (QEC). The QEC scores were found to be very high for the shoulder/arm, wrist/hand and neck, whereas the scores for the back were found to be high for static use and moderate for moving. On the basis of discussions the following conclusions can be drawn; 1. The present working posture of air filling operator is not appropriate and used ergonomic principles to redesign the posture and work station to reduce the WMD. 2. Either made platform for the vehicles on which vehicles come turn by turn and operator fill the air in the tube/tyre at standing position. Or design an air gun to fill the air in the tube/tyre. 3. A robot can be designed for this purpose because work is in repetitive in nature. REFERENCES [1] Kuorinka I, Josson B, Kilbom A.(1987), Standardized Nordic questionnaires for the analyses of musculoskeletal symptoms. 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